Transcript Annelids, arthropods, echinoderms

BSC 2011L
Phylum Annelida
Segmented worms
 Circular and
longitudinal muscles
work against fluid
filled coelom to
produce changes in
width and length
 Digestion – complete
 Circluation – closed
(5 lateral hearts)
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Phylum Annelida
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Class Oligiochaeta
 Earthworms
 Found in soil
 Can reach 3 meters!
Phylum Annelida
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Class Polychaeta
 Sand worms, feather dusters
 Almost all marine
 Live in substrate
Phylum Annelida
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Class Hirudinea
 Leeches
 “bloodsuckers”
Phylum Annelida
Class Oligiochaeta
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Animal:
Symmetry:
Body cavity:
Digestion:
gizzard, etc
Circulation:
Segmentation:
Appendages:
Nervous:
Habitat:
Respiration:
Excretion:
Locomotion:
Support:
Earthworm
Bilateral
coelomate – protostome
complete – mouth, esophagus, crop,
closed, 5 hearts
yes
none
dorsal brain, ventral nerve cord
moist soils
diffusion through body surface
2 lateral tubes
circular and longitudinal muscles, setae
hydrostatic skeleton
Earthworm model
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Earthworm cross-section
http://www.deanza.edu/faculty/mccauley/6a-labs-annelid-01.htm
Earthworm Dissection
Phylum Mollusca
Mostly marine but some
are freshwater and
terrestrial
 3 part body
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 Muscular foot –
locomotion
 Visceral mass – internal
organs
 Mantle – encloses
visceral mass and may
secrete shell
Digestion – complete
 Circulation – open
(except for cephalopods
that are closed)
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Phylum Mollusca
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Class Polyplacophora
 “many plated”
 Chitins
Phylum Mollusca
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Class Gastropoda
 “stomach foot:
Phylum Mollusca
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Class Bivalvia
Phylum Mollusca
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Class Cephalopoda
 “Head-foot”
Phylum Mollusca
Class Bivalvia
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Animal:
Symmetry:
Body cavity:
Digestion:
Circulation:
Segmentation:
Appendages:
Nervous:
Habitat:
Respiration:
Excretion:
Locomotion:
Support:
Clam
bilateral
coelomate – protostome
complete, filter feeders
open, blue blood, heart, blood vessels
none
none
3 ganglia connected by nerves
aquatic
gills
nephridia in kidney
muscular foot
shell
Clam model
Phylum Mollusca
Class Cephalopoda
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Animal:
Symmetry:
Body cavity:
Digestion:
Circulation:
Segmentation:
Appendages:
Nervous:
Habitat:
Respiration:
Excretion:
Locomotion:
Support:
squid
bilateral
coelomate – protostome
complete, beak jaws
closed, 3 hearts
none
8 arms, 2 tentacles
brain of 3 fused ganglia, eye
aquatic
gills
nephridia in kidney
muscular mantle, jet propulsion
shell reduced to pen